I'm not sure what point you are making.

As to my point. For the same reasons I would expect the content
models of xsl:next-match, xsl:apply-templates and xsl:apply-imports
to be the same.

while the select attribute on xsl:copy is a minor improvement, I'm not
sure why you expect the content model to be the same as xsl:copy-of. the
use is completely different: the content of xsl:copy is _constructed_
nodes that are copied into the node created by xsl:copy.

<xsl:copy>
<foo/>
</xsl:copy>